Said pipe is intended to transport a cryogenic fluid derived for example from a gas liquefying process. The transported fluid is liquefied natural gas in particular having a boiling point lower than −163° C.
More generally, a cryogenic fluid transported by the pipe has a boiling point lower than 0° C.
Natural gas extracted from the ground is a major source of fuel that can be recovered.
To transport natural gas in gaseous form from its production site to a receiving site it is known to use pipelines. However, in numerous cases in particular when the production site is located in a body of water, it is simpler and more economical to transfer natural gas in liquid from to reduce the volume thereof during transport and facilitate storage and handling.
However, the handling of cryogenic fluids and in particular the offloading of cryogenic fluid from a floating liquefaction plant to a transport vessel, or from a transport vessel to a storage installation on land must be carried out in the vicinity of the shore, often by means of articulated arms connecting the vessel to the plant or to the storage installation.
Said articulated arms are not adapted for cases in which loading and offloading operations are performed at a distance from the shore in areas that are scarcely protected, in particular when the liquefaction units are positioned on floating installations of <<FLNG>> type.
In this case, the offloading of the liquefied gas can only be carried out when weather conditions are calm, which may make plant operation difficult.
In addition, flexible pipes of bonded or non-bonded type known for unloading hydrocarbon fluids at ambient temperature and are not suitable for transporting cryogenic fluids at temperatures lower than −40° C./−50° C. having regard to the very low temperatures of cryogenic fluids and their special properties.
To remedy this problem, application WO 2011/092440 by the Applicant proposes a flexible pipe which is particularly adapted for the fluid transport through a volume of air. On account of the heat insulating layers arranged in this pipe it is a floating pipe.
Therefore this pipe is not adapted as such for the subsea transfer of cryogenic fluid.
In this respect, U.S. Pat. No. 7,543,613 discloses an installation for transferring fluid between two vessels, comprising a catenary flexible conduit under the surface of the water to limit the impact of weather conditions on the fluid transfer system and improve the safety of operations.
To obtain such catenary configuration the conduit is weighted with a ballast assembly. However this document does not give any indication regarding the structure of this assembly. In particular, the ballast assembly must be capable of weighting the conduit without damaging the heat insulation and the mechanical properties thereof.